Computer-based telecommunications systems have proliferated in the last few years, in part due to the proliferation of high-speed personal computers and low cost equipment now available. When combined with high-speed telephone switching lines, these systems have exhibited rapid advancements in technology and versatility. One of these advancements is the delivery of calling services. These new services range from familiar voice processing services, such as voice mail and interactive voice response, to other advanced services like flexible call forwarding, text-to-voice prompting, and voice recognition. Management and delivery of calling services is collectively referred to as call processing.
Large telephone companies now realize the potential of delivering calling services to a wider population and have begun to offer more services. Many local carriers currently offer call waiting, call forwarding, and voice mail. Most long distance companies also offer calling services, often through their 800 number services. In addition, the rapid advancements in telephony and heightened consumer demand for calling services have spurred the companies who own telephone switches and networks to design and implement new and more sophisticated services.
Telephone service providers rely on switch vendors (such as AT&T and Northern Telecom) to introduce new services through modifications at the switch level. This presents several problems. For example, switch modifications lengthen turnaround time for introducing new services because the local carrier must rely on the switch vendors to update the switch and roll out new services. When the switch vendors finally decide to introduce a new service, the introduction is normally on a national scale, decreasing any chance for differentiation and competition for new services at the local level. In addition, switch manufacturers must rewrite the software that controls the switches to introduce new calling services, further exacerbating the problems of difficult modification and slow introduction of new services.
In response, the industry developed a next generation network design called Advanced Intelligent Network (AIN) architecture. Instead of lumping all calling services into the switch, AIN architecture groups intelligence into peripheral computer systems that can more effectively and efficiently deliver calling services. The concept is to maintain the existing network of generic switches that perform call connection, but to transfer "intelligent" operations to peripheral computers. In such a manner, relatively inexpensive peripheral computers can provide more flexible and efficient call processing.
In managing and delivering calling services, these call processing computers perform a wide variety of functions, ranging from providing simple tasks or resources to managing the overall delivery of calling services. The term call processor refers to any device that executes functions necessary to deliver calling services.
The call processing of 800 calls is a simple example of how a precursor to the AIN concept operates. When a caller places an 800 call, the local switch that receives the call recognizes the number as a special call and defers to an external device for information on how to route the call. The external device is a database containing all of the 800 numbers, and the switch sends a data message to the database requesting routing information. The database performs a lookup to translate the 800 number dialed by the caller into a traditional ten digit number containing an area code and prefix, and sends the translated number to the switch. The switch then routes the call Using the traditional ten digit number. AT&T and other long distance carriers maintain the continually changing 800 number database in central locations. By setting up one or only a few databases, any changes in 800 number service can be made simply and efficiently without having to reprogram every switch each time the database changes. The concept of the switch deferring to a peripheral device to determine how to route the call, rather than relying on its hard-coded logic, is typical of a precursor to the AIN architecture.
The concept of AIN, however, has evolved, and thus takes on several definitions. Early attempts to deliver calling services, termed hybrid AIN architecture, off-load a portion of the switch intelligence, but still require the switch to maintain direct control over call management. The 800 number service is typical of this early architecture, where the switch does not relinquish control over the call but requests data from a central database.
Current AIN architecture delivers calling services through use of service control points (SCPs). An SCP receives a data package from the switch when the switch requires assistance in routing the call or providing a calling feature. Thus, the intelligence to process calls is off-loaded from the switch to the SCP. Local carriers can design and release new calling services by modifying the SCP software, which provides an advantage over the hybrid AIN architecture. The SCP, rather than the switch, assumes control over call processing.
The SCP in the current AIN architecture receives data packages from the switch and manages call processing. The SCP also delegates many of the tasks of call processing to "intelligent" peripherals (IPs). IPs provide a variety of resources, such as voice prompting, digit collecting, and voice recognition, while operating as slave processors to the SCP. The SCP defers a small portion of the call processing to an IP, but immediately regains control of the call after the IP executes a simple task.
A current AIN architecture may also include a service node (SN), which is a stand-alone platform that autonomously delivers calling services. An SN is connected to the switch and dedicated to deliver a particular calling service, such as voice mail, automated attendant, or fax server functions. Unlike the IP which operates as a slave to the SCP, the SN operates for the most part autonomously. The telecommunications switch actually patches the call to the SN and the SN processes the call autonomously without much direction from the switch or the SCP. Therefore, AIN architecture currently supports using both a dedicated SN for autonomously delivering a particular calling service and an SCP with access to the resources of an IP for managing delivery of calling services.
Thus, the current landscape of call processing at the local carrier level continues to evolve, with several variations in existence. Consequently, a need has arisen for a system that is compatible with current and unsettled industry standards, and yet easily modifiable and reconfigurable to meet the future specifications of switch manufacturers, local carriers, and their customers.